You assuptiom could be right but...
Consider a document with a image and a script.
When it loads, there are 3 load events that are fired in the document,
one for the image, another to the script and a last one for the
document. Only the load event for document bubbles. The other two
don't, but they have their capturing phases. Therefore any capturing
event listener will be fired upon each of these load events, but since
of 2 don't bubble, non-capturing event listeners will fire only once